JPH11197921A - Cutting edge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting edge capable of cutting a material to be cut with small resistance and ensuring the strength of the edge. SOLUTION: The cutting face 19 (19a, 19b) of the edge in a cutting edge comprises plural cutting faces difference in rake, wherein the width of the cutting face 19a with a small rake is smaller than that of the cutting face 19b with a large rake, and the rear part of the cutting face 19a with a small rake is increased in rake so as to be flush with the rear part of the adjacent cutting face 19b with a large rake, whereby the cutting resistance is reduced at the cutting face 19b with a large rake, and the strength of the edge is held by the cutting face 19a with a small rake so that screw-in and boring are enabled with light force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting blade used for a drill screw or a cutting tool having a drill function at a tip thereof,
The present invention relates to a drill screw and a cutting tool provided with the cutting blade.

[0002]

2. Description of the Related Art FIG. 5 shows a structure of a cutting blade 1 of a drill screw or a cutting tool having a drill function at a tip. In such a cutting blade 1, an important factor that affects a cutting performance is a cutting speed. In addition to the cutting conditions such as the above, the "rake angle a" of the rake face 3 for scooping the surface of the workpiece A having a predetermined depth with the blade edge 2 and the structure of the workpiece A slips due to the compressive force applied by the blade edge 2. When the rake face 3 is pushed upward while being broken by the rake face, the "shear angle b" which is the angle with the surface of the workpiece A or the surface of the workpiece A at the trace of the rake is properly applied. The setting of the “flank angle c” of the flank surface 4 which is the facing surface having an appropriate interval is exemplified.

Generally, when cutting the workpiece A with a small resistance, it is necessary to increase the "rake angle a" formed between the rake face and the vertical line and to compress and break the workpiece A to scoop. It is said that the "shear angle b" should be increased so that the workpiece A is separated and scooped.

[0004]

By the way, when the shear angle b of the cutting blade 1 is set to be large, the angle of the cutting edge 2 determined between the rake face 3 and the flank face 4 becomes small, the strength is reduced, and the rigidity is reduced. When trying to cut an object, there is a problem that the cutting edge 2 does not have.

Accordingly, an object of the present invention is to provide a cutting blade capable of cutting an object to be cut with a small resistance and ensuring the strength of the cutting edge, and a drill screw and a cutting tool using the cutting blade. Is to provide.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention of claim 1 employs a configuration in which the rake face of the cutting edge comprises a plurality of rake faces having different rake angles.

A second aspect of the present invention is the invention according to the first aspect, wherein the width of the rake face having a small rake angle is smaller than the width of the rake face having a large rake angle.

According to a third aspect of the present invention, in the first or second aspect, the rear portion of the rake face having a small rake angle has a large rake angle and is flush with the rear portion of the adjacent rake face having a large rake angle. Is adopted.

According to a fourth aspect of the present invention, at least one cutting blade according to any one of the first to third aspects of the present invention is a drill screw provided at a tip of a shaft portion.

According to a fifth aspect of the present invention, there is provided a cutting tool according to any one of the first to third aspects, wherein at least one cutting blade is provided at a tip of a shaft portion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A to 1C show an embodiment of a drill screw 11 provided with a cutting blade.
Has a cutting blade 14 at the front end of a shaft portion 13 having a screw 12 formed on the outer periphery and a head portion 15 at a rear end.

The cutting blade 14 is provided with a conical portion 17 at the tip of a circular shaft portion 16 connected to the distal end side of the shaft portion 13, and on both sides of the conical portion 17 and the outer surface of the circular shaft portion 16 sandwiching the axis. At a position, an axial recess 18 is formed from the tip of the conical portion 17 to the upper end of the circular shaft portion 16, and a side edge portion of the recess 18 located rearward with respect to the screwing rotation direction of the drill screw 11 is As shown in FIG. 3, a cutting edge 21 having a rake face 19 and a flank 20 is provided, and the rake face 19 of the cutting edge 21 is formed of a plurality of rake faces 19a and 19b having different rake angles.

The cutting edge 21 includes a conical portion 17 and a circular shaft portion 16.
The rake face 19 of the cutting edge 21 over the entire length of the side edge portion of the recess 18 described above has a rake face 19a having a small rake angle with respect to a perpendicular and a rake face 19b having a large rake angle.
4, the width W1 of the rake face 19a having a small rake angle is smaller than the width W2 of the rake face 19b having a large rake angle, and as shown in FIG. Small rake face 19
The rake angle of the rear part of a is larger, and is flush with the rear part of the adjacent rake face 19b having a large rake angle.

Here, the rake face 1 having a small rake angle
By making the width W1 of 9a smaller than the width W2 of the rake face 19b having a large rake angle, it is possible to effectively reduce the cutting resistance while maintaining the strength of the cutting edge 21.

As described above, a triangular step 22 is formed in the portion adjacent to the rake face 19a having a small rake angle and the rake face 19b having a large rake angle as shown in FIG. 2A and 2B show an embodiment of a cutting tool 31 which is a drill provided with a cutting blade. As is well known, a tip cutting blade 14 (a cutting edge) of a drill body 33 having a twist groove 32 is known. ) Has a structure in which rake faces 19a having a small rake angle and rake faces 19b having a large rake angle are alternately provided in the same manner as in the embodiment of the drill screw 11 described above.

The cutting blade of the present invention is configured as described above. In the embodiment of the drill screw 11, when the drill screw 11 is screwed in, the cutting blade 14 first drills a prepared hole in the threaded object. Subsequently, the shaft 13 is screwed into the pilot hole by the screw 12.

Further, in the case of the embodiment of the cutting tool 31, the tip cutting blade 14 enters while cutting the object to be drilled, discharges cutting chips by the twist groove 32 of the drill body 33, and forms a hole in the object to be drilled. Drill.

When the cutting blade 14 is screwed or drilled, the cutting edge of the rake face 19b having a large rake angle enables cutting with a small resistance. At the same time, the cutting edge of the adjacent rake face 19a having a small rake angle has As a result, the strength of the entire cutting blade 14 is secured, and the cutting performance can be improved while maintaining the strength of the cutting edge.

[0020]

As described above, according to the present invention, the rake face of the cutting edge is formed by a plurality of rake faces having different rake angles. At the same time, the cutting edge of the adjacent rake face with a small rake angle secures the strength of the entire cutting edge, thereby improving the cutting performance while maintaining the strength of the cutting edge as a whole cutting blade. Become.

The width of the rake face with a small rake angle is
Since the width of the rake face with a large rake angle is smaller than the width of the rake face with a large rake angle, cutting resistance can be effectively reduced, and the rake angle at the rear of the rake face with a small rake angle becomes larger and the same as the rear part of the adjacent rake face with a large rake angle. By using the surface, the discharge property of the cutting waste is improved.

Further, in the drill screw provided with the cutting blade of the present invention, screwing can be performed with a small force, and in the drill provided with the cutting blade of the present invention, drilling can be performed with a small force.

[Brief description of the drawings]

1A is a front view of a drill screw, FIG. 1B is an enlarged front view of a cutting edge part of the same, and FIG. 1C is a bottom view of the cutting edge part of the same.

2A is a front view of a cutting tool, and FIG. 2B is a bottom view of a cutting edge portion of the cutting tool.

FIG. 3 is a sectional view of a cutting blade.

FIG. 4 is an explanatory view showing the structure of a cutting blade.

FIG. 5 is a sectional view showing a cutting state of a conventional cutting blade.

[Explanation of symbols]

 Reference Signs List 11 drill screw 14 cutting blade 19 rake face 19a rake face with small rake angle 19b rake face with large rake angle 20 flank face 21 cutting edge 31 cutting tool

Claims (5)

[Claims] 1. A cutting blade characterized in that the rake face of the cutting edge comprises a plurality of rake faces having different rake angles. 2. The cutting blade according to claim 1, wherein the width of the rake face having a small rake angle is smaller than the width of the rake face having a large rake angle. 3. A rake face having a small rake angle has a large rake angle at a rear portion thereof, and the rear portion of the rake face having a large rake angle has the same plane as a rear portion of the rake face having a large rake angle.
The described cutting blade. 4. A drill screw, wherein at least one cutting blade according to claim 1 is provided at a tip of a shaft portion. 5. A cutting tool, wherein at least one cutting blade according to claim 1 is provided at a tip of a shaft portion.